X Plane Sr 71

The SR-71 Blackbird was retired by the USAF in 1998, leaving what was considered a coverage gap between surveillance satellites, manned aircraft, and unmanned aerial vehicles for intelligence, surveillance and reconnaissance (ISR) and strike missions.

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Two SR-71 aircraft were used by NASA as testbeds for high-speed, high-altitude aeronautical research.

The aircraft, an SR-71A and an SR-71B pilot trainer aircraft were based at NASA's Dryden Flight Research Center, Edwards, Calif. They have been loaned to NASA by the U.S. Air Force. Developed for the USAF as reconnaissance aircraft more than 30 years ago, SR-71s are still the world's fastest and highest-flying production aircraft.

The SR-71 is the pioneer of stealth, though ours doesn’t use the fictional Shi’ar alien cloaking technology of the X-jet. It wasn’t easy creating an aircraft that was virtually undetectable to enemy radar: The aircraft’s surfaces were designed to avoid reflecting radar signals, the engines were placed in a subtle mid-wing position, and the paint included a radar-absorbing element. Just a bit of sightseeing on my way around the world in an SR-71 Blackbird. Flight edited for entertainment purposes.

The aircraft can fly more than 2200 miles per hour (Mach 3+ or more than three times the speed of sound) and at altitudes of over 85,000 feet. This operating environment makes the aircraft excellent platforms to carry out research and experiments in a variety of areas — aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies and sonic boom characterization.

Data from the SR-71 high-speed research program may be used to aid designers of future supersonic/hypersonic aircraft and propulsion systems, including a high-speed civil transport.

The SR-71 program at Dryden was part of NASA's overall high-speed aeronautical research program, and projects involve other NASA research centers, other government agencies, universities and commercial firms.

Research at Mach 3

One of the first major experiments to be flown in the NASA SR-71 program was a laser air-data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data such as angle of attack and sideslip normally obtained with small tubes and vanes extending into the air stream or from tubes with flush openings on an aircraft's outer skin. The flights provided information on the presence of atmospheric particles at altitudes of 80,000 feet and above where future hypersonic aircraft will be operating. The system used six sheets of laser light projected from the bottom of the 'A' model. As microscopic-size atmospheric particles passed between the two beams, direction and speed were measured and processed into standard speed and attitude references. An earlier laser air data collection system was successfully tested at Dryden on an F-l04 testbed.

'The Last Hot Flight' painting © Dru Blair

The first of a series of flights using the SR-71 as a science camera platform for NASA's Jet Propulsion Laboratory, Pasadena, Calif., was flown in March 1993. From the nosebay of the aircraft, an upward-looking ultraviolet video camera studied a variety of celestial objects in wavelengths that are blocked to ground-based astronomers.

The SR-71 has also been used in a project for researchers at the University of California-Los Angeles (UCLA) who were investigating the use of charged chlorine atoms to protect and rebuild the ozone layer.

In addition to observing celestial objects in the various wavelengths, future missions could include 'downward' looking instruments to study rocket engine exhaust plumes, volcano plumes and the Earth's atmosphere, as part of the scientific effort to reduce pollution and protect the ozone layer.

The SR-71, operating as a testbed, also has been used to assist in the development of a commercial satellite-based, instant wireless personal comunications network, called the IRIDIUM system, under NASA's commercialization assistance program. The IRIDIUM system was being developed by Motorola's Satellite Communications Division. During the development tests, the SR-71 acted as a 'surrogate satellite' for transmitters and receivers on the ground.

The SR-71 also has been used in a program to study ways of reducing sonic boom overpressures that are heard on the ground much like sharp thunderclaps when an aircraft exceeds the speed of sound. Data from the study could eventually lead to aircraft designs that would reduce the 'peak' of sonic booms and minimize the startle affect they produce on the ground.

Instruments at precise locations on the ground record the sonic booms as the aircraft passes overhead at known altitudes and speeds. An F-16XL aircraft was also used in the study. It was flown behind the SR-71, probing the near-field shockwave while instrumentation recorded the pressures and other atmospheric parameters.

In November 1998 the SR-71 completed the NASA/Lockheed Martin Linear Aerospike SR-71 experiment (LASRE). LASRE was a small, half-span model of a lifting body with eight thrust cells of an aerospike engine, mounted on the back of an SR-71 aircraft and operating like a kind of 'flying wind tunnel.'

During seven flights, the experiment gained information that may help Lockheed Martin predict how operation of aerospike engines at altitude will affect vehicle aerodynamics of a future reusable launch vehicle.

Dryden has a decade of past experience at sustained speeds above Mach 3. Two YF-12 aircraft were flown at the facility between December 1969 and November 1979 in a joint NASA/USAF program to learn more about the capabilities and limitations of high speed, high-altitude flight. The YF-12s were prototypes of a planned interceptor aircraft based on a design that later evolved into the SR-71 reconnaissance aircraft.

Research information from the YF-12 program was used to validate analytical theories and wind-tunnel test techniques to help improve the design and performance of future military and civil aircraft. The American supersonic transport project of the late 1960s and early 1970s would have benefited greatly from YF-12 research data. The aircraft were a YF-12A (tail #935) and a YF-12C (tail #937). Tail number 937 was actually an SR-71 that was called a YF-12C for security reasons. These aircraft logged a combined total of 242 flights during the program. A third aircraft, a YF-12A (tail #936), was flown by Air Force crews early in the program. It was lost because of an inflight fire in June l971. The crew was not hurt.

The YF-12s were used for a wide range of experiments and research. Among the areas investigated were aerodynamic loads, aerodynamic drag and skin friction, heat transfer, thermal stresses, airframe and propulsion system interactions, inlet control systems, high-altitude turbulence, boundary layer flow, landing gear dynamics, measurement of engine effluents for pollution studies, noise measurements and evaluation of a maintenance monitoring and recording system. On many YF-12 flights medical researchers obtained information on the physiological and biomedical aspects of crews flying at sustained high speeds.

From February 1972 until July 1973, a YF-12A was used for heat loads testing in Dryden's High Temperature Loads Laboratory (now the Thermostructures Research Facility). The data helped improve theoretical prediction methods and computer models of that era dealing with structural loads, materials and heat distribution at up to 800 degrees (F), the same surface temperatures reached during sustained speeds of Mach 3.

SR-71 Specifications and Performance

The SR-71 was designed and built by the Lockheed Skunk Works, now the Lockheed Martin Skunk Works. SR-71s are powered by two Pratt and Whitney J-58 axial-flow turbojets with afterburners, each producing 32,500 pounds of thrust. Studies have shown that less than 20 percent of the total thrust used to fly at Mach 3 is produced by the basic engine itself. The balance of the total thrust is produced by the unique design of the engine inlet and 'moveable spike' system at the front of the engine nacelles and by the ejector nozzles at the exhaust which burn air compressed in the engine bypass system.

Speed of the aircraft is announced as Mach 3.2 — more than 2000 miles per hour (3218.68 kilometers per hour). They have an unrefueled range of more than 2000 miles (3218.68 kilometers) and fly at altitudes of over 85,000 feet (25908 meters).

As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees (F). The aircraft are 107.4 feet (32.73 meters) long, have a wing span of 55.6 feet (16.94 meters, and are l8.5 feet (5.63 meters) high (ground to the top of the rudders when parked). Gross takeoff weight is about 140,000 pounds (52253.83 kilograms), including a fuel weight of 80,000 pounds (29859.33 kilograms).

The airframes are built almost entirely of titanium and titanium alloys to withstand heat generated by sustained Mach 3 flight. Aerodynamic control surfaces consist of all-moving vertical tail surfaces above each engine nacelle, ailerons on the outer wings and elevators on the trailing edges between the engine exhaust nozzles.

The two SR-71s at Dryden have been assigned the following NASA tail numbers: NASA 844 (A model), military serial 64-17980, manufactured in July 1967, and NASA 831 (B model), military serial 64-17956, manufactured in September 1965. From 1991 through 1994, Dryden also had another 'A' model, NASA 832, military serial 64-17971, manufactured in October 1966. This aircraft was returned to the USAF inventory and was the first aircraft reactivated for USAF reconnaissance purposes in 1995.

The SR-71 last flight took place in October 1999.

Development History

The SR-71 was designed by a team of Lockheed personnel led by Clarence 'Kelly' Johnson, at that time vice president of the Lockheed's Advanced Development Company, commonly known as the 'Skunk Works.'

The basic design of the SR-71 and YF-12 aircraft originated in secrecy in the late l950s with the aircraft designation of A-11. Its existence was publicly announced by President Lyndon Johnson on Feb. 29, 1964, when he announced that an A-11 had flown at sustained speeds of over 2000 miles per hour during tests at Edwards Air Force Base, Calif.

Development of the SR-71s from the A-11 design, as strategic reconnaissance aircraft, began in February 1963. First flight of an SR-71 was on Dec. 22, 1964.

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X Plane Sr 71
According to the comic books, Superman could fly 'faster than a speeding bullet.' That's nothing. The SR-71 Blackbird set a jet speed record of Mach 3.2. That's more than three times faster than the speed of sound. The X-15 rocket plane set a record for winged vehicles with a speed of Mach 6.7. They're both slowpokes.
Image to right: The X-43A is also called the Hyper-X. Credit: NASA
NASA beat both of those records earlier this year with a new airplane called the X-43A. This plane is also known as the Hyper-X. In March 2004, the Hyper-X set a new record for air-breathing aircraft of about 5,000 miles per hour (mph). This is almost seven times the speed of sound. But, now, even that record has been left in the dust. In fact, the new record holder reached a speed almost as great as the records of the Blackbird and the X-15 put together. Now, that's fast.
In November 2004, the X-43A flew for the final time. It set a new speed record almost 10 times faster than the speed of sound. Early data showed the 12-foot-long unmanned plane reached about 7,000 mph. This is almost Mach 9.8. It reached an altitude of about 110,000 feet.
Image to left: The X-43A is much faster than the speed of sound. Credit: NASA
The X-43A is the world's first hypersonic jet airplane. This means that it went faster than Mach 5. The X-43A uses a new technology called the scramjet engine. The term scramjet is short for supersonic-combustion ramjet. This means that the plane uses supersonic air from the atmosphere mixed with fuel to propel itself. Until now, the fastest planes have reached those advanced speeds with the help of rockets. Hyper-X planes, though, are air-breathing jets.
In normal turbojet engines, the compressor section (the fan blades) compresses the air to speed it through the engine at great speeds. That's what makes the plane move forward. In rockets, fuel and oxygen are combined and burned to create the blast of energy. In air-breathing vehicles, though, vent inlets on the outside of the plane scoop the air from outside. Because the X-43A is going so fast, the air is 'rammed' into the engine. This gives the engine the name 'ramjet.'
Ramjet engines use a subsonic stream of air through the engine to push the aircraft at supersonic (above the speed of sound) speeds. When the air flowing through the engine stays at supersonic speeds, it's called a scramjet. Scramjets and ramjets need no moving parts in their engines. The thrust is created by rapidly forcing airflow through the engine. Since they don't have to carry oxygen for fuel (like rockets do), they weigh less. Another plus is that scramjets can be throttled back and flown more like an airplane. Rockets have a harder time of reducing the amount of thrust they create.
Image to right: A launch aircraft takes off with the X-43A. Credit: NASA
During the recent test flight, the X-43A was carried aloft by a B-52B launch aircraft. The X-43A was attached to a Pegasus booster rocket. This rocket was attached under one of the B-52B's wings. Once the B-52B reached the right height, it released the Pegasus rocket. This rocket then boosted the Hyper-X to its test speed. The X-43A then separated from the Pegasus, and used its scramjet engine for about 10 seconds of powered flight. When the engine shut down, the aircraft glided into the Pacific Ocean, according to plan. The Hyper-X is not reusable.
The November 16 flight was the third test of the X-43A. A June 2001 test ended in failure. The aircraft had to be destroyed when it began to fly off course. Scientists found that the problem was caused by the control system of the booster rocket.
Image to left: The success of the X-43A has opened a door into the future of transportation. Credit: NASA
The Hyper-X was a great success. At the speed at which the X-43A flew, it could go from New York to Tokyo in under an hour. By not needing to carry an onboard supply of oxygen, a scramjet engine could help carry large payloads into space more efficiently. By turning theory into reality, NASA has opened a door into the future of transportation on this world and beyond.

X Plane 11 Sr 71 Checklist

Mach -- a number representing the ratio of the speed of a body (as an aircraft) to the speed of sound in a surrounding medium (as air)

X Plane Sr 71 For Sale

subsonic -- of, relating to, or being a speed less than that of sound in air
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